CVE-2026-40198

libnet-cidr-lite-perl: Net::CIDR::Lite versions before 0.23 for Perl does not validate IPv6 group count, which may allow IP ACL bypass

CVE-2026-40198 is fixed in 2 products on 1 platform, first by libnet-cidr-lite-perl 0.21-1ubuntu0.18.04.1~esm1, released April 10, 2026. It is not reported as exploited. Patch Radar priority: High.

High
CVSS
7.5
high
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0032
24th percentile

Net::CIDR::Lite versions before 0.23 for Perl does not validate IPv6 group count, which may allow IP ACL bypass. _pack_ipv6() does not check that uncompressed IPv6 addresses (without ::) have exactly 8 hex groups. Inputs like "abcd", "1:2:3", or "1:2:3:4:5:6:7" are accepted and produce packed values of wrong length (3, 7, or 15 bytes instead of 17). The packed values are used internally for mask and comparison operations. find() and bin_find() use Perl string comparison (lt/gt) on these values, and comparing strings of different lengths gives wrong results. This can cause find() to incorrectly report an address as inside or outside a range. Example: my $cidr = Net::CIDR::Lite->new("::/8"); $cidr->find("1:2:3"); # invalid input, incorrectly returns true This is the same class of input validation issue as CVE-2021-47154 (IPv4 leading zeros) previously fixed in this module. See also CVE-2026-40199, a related issue in the same function affecting IPv4 mapped IPv6 addresses.

Where it's fixed

ProductFixed inFixReleased
Linux
libnet-cidr-lite-perl · Debian 12.15 (bookworm) 0.22-3~deb12u1 DEBIAN-CVE-2026-40198 Apr 10, 2026
libnet-cidr-lite-perl · Debian 13.5 (trixie) 0.22-3~deb13u1 DEBIAN-CVE-2026-40198 Apr 10, 2026
libnet-cidr-lite-perl · Debian 14 0.22-3 DEBIAN-CVE-2026-40198 Apr 10, 2026
libnet-cidr-lite-perl · Ubuntu 18.04.6 LTS (bionic) 0.21-1ubuntu0.18.04.1~esm1 libnet-cidr-lite-perl 0.21-1ubuntu0.18.04.1~esm1 Apr 10, 2026
libnet-cidr-lite-perl · Ubuntu 20.04 LTS (focal) 0.21-2ubuntu0.1+esm1 libnet-cidr-lite-perl 0.21-2ubuntu0.1+esm1 Apr 10, 2026
libnet-cidr-lite-perl · Ubuntu 22.04.1 LTS (jammy) 0.22-1ubuntu0.1 libnet-cidr-lite-perl 0.22-1ubuntu0.1 Apr 10, 2026
libnet-cidr-lite-perl · Ubuntu 24.04.5 LTS (noble) 0.22-2ubuntu0.24.04.1 libnet-cidr-lite-perl 0.22-2ubuntu0.24.04.1 Apr 10, 2026
libnet-cidr-lite-perl · Ubuntu 25.10 (questing) 0.22-2ubuntu0.25.10.1 libnet-cidr-lite-perl 0.22-2ubuntu0.25.10.1 Apr 10, 2026
libnet-cidr-lite-perl · Ubuntu 26.04.1 LTS (resolute) 0.22-2ubuntu0.26.04.1 libnet-cidr-lite-perl 0.22-2ubuntu0.26.04.1 Apr 10, 2026
perl-Net-CIDR-Lite · amzn 2023 0.22-8.amzn2023.0.1 ALAS2023-2026-1624 Apr 27, 2026

Patch Radar data is free to use with attribution. Terms and how to credit it.

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.